The International HapMap Project, formed in October 2002, will develop a haplotype map of the human genome. The HapMap will enable the discovery of sequence variants that affect common disease, the development of diagnostic tools, and the ability to choose targets for therapeutic intervention. The HapMap consortium will characterize the common patterns of genetic variation using single nucleotide polymorphisms by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them. DNA samples from populations with ancestry from parts of Africa, Asia, and Europe will be used. Genetic and statistical analyses of the data are the responsibility of three funded analysis groups at the Whitehead Institute of Biomedical Research (David Altshuler), Johns Hopkins University (Aravinda Chakravarti) and Oxford University (Peter Donnelly). Statistical and population genetic methods for the analysis and interpretation of the HapMap genotypes are critical and methods to infer association patterns are in their early phase. There is a great need to spur additional development of analysis methods and to engage new investigators in this exciting project. To extend the utility of the HapMap project we wish to propose an open working meeting with a diverse group of analytical investigators in each of 2004 and 2005. We expect to include 40 investigators from the existing HapMap project and 60 from outside the project. The aims of the meeting will be to stimulate new methods development in this arena and to use a recent freeze of the data for intensive analysis by a variety of statistical methods by any investigator with interest. A meeting of invited talks and talks and posters based on abstract submissions from data analysis or methods development will be held.